Re: light

Jim Black wrote:
Sue... wrote:
Sue... wrote:
Jim Black wrote:
Sue... wrote:
The center of a 'photon' doesn't leave the atom until it is absorbed
so any sort of 'in flight' gravitational interaction with
mass is as absurd as trying to quantify a photon's size.

http://www.google.com/search?hl=en&lr=&q=starlight+bent+eclipse

http://www.google.com/search?hl=en&lr=&safe=off&q=bertotti+refraction&btnG=Search

<< In order to bend the light toward the star one needs
to delay the wavefront near the star. >>
http://www.astro.ucla.edu/~wright/deflection-delay.html

Your post seemed to imply that there was no gravitational interaction
between light and matter (If I misinterpreted you, I apologize).

The apology is mine. I was trying to say that gravity doesn't
interact directly with light. Okun says it better:

http://arxiv.org/abs/hep-th/0506053
http://arxiv.org/abs/physics/9907017

Light doesn't interact with light so why should it interact with
gravity?

I don't know what you call that, but I would call it a gravitational
influence of the matter on the light. Matter tells space and time how
to curve, and space and time tell the light wave which way to go.

No !!! :-)

"Space-Time tells matter how to move. Matter tells space-time
how to curve." --J.A. Wheeler

Space and time are not the same as the mathematical abstraction
of Minkowski space time.
<< space-time has a non-isotropic nature which is quite unlike
Euclidian space with its positive definite metric. According to the
relativity principle, all physical laws are expressible as
interrelationships
between 4-tensors in space-time. >>
"Space-time"
http://farside.ph.utexas.edu/teaching/em/lectures/node113.html

Wheeler is speaking of a co-ordinate system that does not
have pure temporal and spatial axes. The too familiar rubber
*** analogy is intended for a lay audience. It totally
misrepresents the 'curvature' in the calculus that describes a
'gravitational field' in four-space.



Electromagnetic fields also possess energy, momentum, and pressure,
which according to general relativity, should have a gravitational
influence on matter.

That seems counter to GR's notion that gravity should propagate
as light.


However, this is small, and I don't know of any
experiment that has verified this prediction directly (you can infer it
indirectly by assuming conservation of momentum).


I would think that would take some shell games with
angular momentum and gravitational force.
Does a top get heavier when it is spinning?

I can infer refrigeration equipment in my car because
ice cream is frozen both at the grocery store and
in my kitchen and all points in between. But I can assure
you, my car doesn't even have air conditioning. ;-)

Sue...

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